As you already stated, the specification does not state any size limits / requirements for types besides Number. So this is definitally left to the implementation. For example, Chrome’s limit on strings seems to be hard coded at around 512mb (and less on 32bit). This puts a limit on the maximally possible allocation request in … Read more
dtoa.c contains two main functions: dtoa(), which converts a double to string, and strtod(), which converts a string to a double. It also contains a lot of support functions, most of which are for its own implementation of arbitrary-precision arithmetic. dtoa.c’s claim to fame is getting these conversions right, and that can only be done, … Read more
To concisely answer your question, everything beneath the LeftHandSideExpression production is a valid LeftHandSideExpression. I think the question you are really asking is: What is a valid LeftHandSideExpression and also assignable? The answer to that is anything that resolves to a Reference which is a well defined concept in the specification. In your example new … Read more
No, you can’t disable strict mode per function. It’s important to understand that strict mode works lexically; meaning — it affects function declaration, not execution. Any function declared within strict code becomes a strict function itself. But not any function called from within strict code is necessarily strict: (function(sloppy) { “use strict”; function strict() { … Read more
There are several things that you can’t emulate from the ECMAScript 5 Object.create method on an ECMAScript 3 environment. As you saw, the properties argument will give you problems since in E3-based implementations there is no way to change the property attributes. The Object.defineProperty method as @Raynos mentioned, works on IE8, but partially, it can … Read more
Infinity and NaN aren’t keywords or anything special, they are just properties on the global object (as is undefined) and as such can be changed. It’s for that reason JSON doesn’t include them in the spec — in essence any true JSON string should have the same result in EcmaScript if you do eval(jsonString) or … Read more
I think a little history lesson is due. JavaScript was originally named Mocha and changed to Livescript but ultimately became JavaScript. It’s important to note that JavaScript came before ECMAscript and the history will tell you why. To start from the beginning, JavaScript derived its name from Java and initially Brendan Eich (the creator of … Read more
You are just using The Comma Operator. This operator only evaluates its operands from left to right, and returns the value from the second one, for example: (0, 1); // 1 (‘foo’, ‘bar’); // ‘bar’ In the context of calling a function, the evaluation of the operand will simply get a value, not a reference, … Read more
Early versions of JavaScript did not allow named function expressions, and because of that we could not make a recursive function expression: // This snippet will work: function factorial(n) { return (!(n>1))? 1 : factorial(n-1)*n; } [1,2,3,4,5].map(factorial); // But this snippet will not: [1,2,3,4,5].map(function(n) { return (!(n>1))? 1 : /* what goes here? */ (n-1)*n; … Read more